Solid-state imaging device

ABSTRACT

Provided is a solid-state imaging device capable of forming a pixel separation groove having a suitable action in a substrate. 
     A solid-state imaging device of the present disclosure includes: a first photoelectric conversion unit and a second photoelectric conversion unit that are provided in a first semiconductor substrate and are adjacent to each other; a first pixel separation groove provided between the first photoelectric conversion unit and the second photoelectric conversion unit not to penetrate through the first semiconductor substrate; and a second pixel separation groove provided to penetrate through the first semiconductor substrate.

TECHNICAL FIELD

The present disclosure relates to a solid-state imaging device.

BACKGROUND ART

When a pixel size of a solid-state imaging device is reduced, there is apossibility that light that is to enter a photoelectric conversion unitof a certain pixel enters a photoelectric conversion unit of anotherpixel to cause crosstalk between the pixels. Therefore, a pixelseparation groove that surrounds each of the photoelectric conversionunits in a plan view is sometimes provided in a substrate for each ofthe photoelectric conversion units.

CITATION LIST Patent Document

-   Patent Document 1: Japanese Patent Application Laid-Open No.    2015-18969-   Patent Document 2: Japanese Patent Application Laid-Open No.    2018-201015-   Patent Document 3: International Publication No. 2017/130723

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

Types of the pixel separation groove include a through groove formed soas to penetrate through the substrate and a non-through groove formed soas not to penetrate through the substrate. The through groove has anadvantage that a light amount range in which a phase difference can beacquired is wide, but has a disadvantage that overflow between pixels ofthe same color is not possible. On the other hand, the non-throughgroove has an advantage that overflow between pixels of the same coloris possible, but has a disadvantage that a light amount range in which aphase difference can be acquired is narrow. It is desirable to achieve apixel separation groove that can obtain both the advantage of thethrough groove and the advantage of the non-through groove.

Therefore, the present disclosure provides a solid-state imaging devicecapable of forming a pixel separation groove having a suitable action ina substrate.

Solutions to Problems

A solid-state imaging device of a first aspect of the present disclosureincludes: first and second photoelectric conversion units that areprovided in a first semiconductor substrate and are adjacent to eachother; a first pixel separation groove provided between the firstphotoelectric conversion unit and the second photoelectric conversionunit not to penetrate through the first semiconductor substrate; and asecond pixel separation groove provided to penetrate through the firstsemiconductor substrate. Therefore, for example, it is possible toobtain an advantage of a non-through groove by the first pixelseparation groove, and it is possible to obtain an advantage of athrough groove by the second pixel separation groove, so that it ispossible to form pixel separation grooves having a suitable action inthe first semiconductor substrate.

Furthermore, in the first aspect, the first pixel separation groove maybe provided from a side of a light incident surface of the firstsemiconductor substrate toward a surface of the first semiconductorsubstrate on a side opposite to the light reflecting surface. Therefore,for example, in a solid-state imaging device of a back-illuminated type,the first pixel separation groove can be formed on a back surface of thefirst semiconductor substrate.

Furthermore, in the first aspect, the second pixel separation groove maybe provided to surround at least the first and second photoelectricconversion units in a plan view. Therefore, for example, crosstalkbetween the first and second photoelectric conversion units and otherphotoelectric conversion units can be suppressed by the second pixelseparation groove.

Furthermore, in the first aspect, the second pixel separation groove mayform a pixel separation groove a pixel separation groove that surroundsthe first and second photoelectric conversion units for each of thephotoelectric conversion units together with the first pixel separationgroove. Therefore, for example, crosstalk between the photoelectricconversion units can be suppressed by the first and second pixelseparation grooves.

Furthermore, in the first aspect, the second pixel separation groove maybe further provided between the first photoelectric conversion unit andthe second photoelectric conversion unit together with the first pixelseparation groove. Therefore, for example, it is possible to increase aproportion of the through groove (second pixel separation groove) to theentire pixel separation groove.

Furthermore, in the first aspect, the second pixel separation groove maysurround N photoelectric conversion units (N is an integer of two ormore) including the first and second photoelectric conversion units, andthe N photoelectric conversion units may correspond to one on-chip lensprovided on the first semiconductor substrate. Therefore, for example, aphotoelectric conversion unit corresponding to a certain on-chip lensand a photoelectric conversion unit corresponding to another on-chiplens can be separated by the through groove (second pixel separationgroove).

Furthermore, in the first aspect, the N photoelectric conversion unitsmay be provided in N pixels which are pixels of the same color.Therefore, for example, a photoelectric conversion unit corresponding toa certain color and a photoelectric conversion unit corresponding toanother color can be separated by the through groove (second pixelseparation groove).

Furthermore, in the first aspect, the second pixel separation groove maysurround N photoelectric conversion units (N is an integer of two ormore) including the first and second photoelectric conversion units, andthe N photoelectric conversion units may correspond to two on-chiplenses provided on the first semiconductor substrate. Therefore, forexample, the photoelectric conversion units can be protected for everytwo on-chip lenses by the through groove (second pixel separationgroove).

Furthermore, in the first aspect, the second pixel separation groove maysurround N photoelectric conversion units (N is an integer of two ormore) including the first and second photoelectric conversion units, andthe N photoelectric conversion units may correspond to N on-chip lensesprovided on the first semiconductor substrate. Therefore, for example,the photoelectric conversion units corresponding to the on-chip lenseson a one-to-one basis can be collectively protected for every multiplephotoelectric conversion units by the through groove (second pixelseparation groove).

Furthermore, in the first aspect, the N may be a square of K (K is aninteger of three or more). Therefore, for example, K×K photoelectricconversion units arranged in a two-dimensional array can be collectivelyprotected by the second pixel separation groove.

Furthermore, the solid-state imaging device of the first aspect mayfurther include a floating diffusion unit provided at a position atleast partially overlapping the first pixel separation groove in a planview in the first semiconductor substrate. Therefore, for example, thefirst photoelectric conversion unit and the second photoelectricconversion unit can share the floating diffusion unit.

Furthermore, in the first aspect, the first pixel separation groove mayinclude a first portion extending in a first direction and a secondportion extending in a second direction, and the floating diffusion unitmay be provided at a position at least partially overlapping anintersection portion between the first portion and the second portion ina plan view in the first semiconductor substrate. Therefore, forexample, the floating diffusion unit can be shared by four photoelectricconversion units including the first and second photoelectric conversionunits.

Furthermore, in the first aspect, the first pixel separation groove mayinclude a first portion extending in a first direction and a secondportion extending in a second direction, and the first direction and thesecond direction may be non-parallel and non-perpendicular to an endsurface of a chip including the solid-state imaging device. Therefore,it is possible to achieve the solid-state imaging device having suitableperformance, for example, even in a case where a front surface of asubstrate can be various surfaces such as a plane {100} and a plane{110}, or in a case where a direction from a notch of the substratetoward the center can be various directions such as a direction <100>and a direction <110>.

Furthermore, the solid-state imaging device of the first aspect mayfurther include first and second transfer transistors that are providedunder the first and second photoelectric conversion units and have gateelectrodes, respectively, being at least partially provided in a firstinterlayer insulating film. Therefore, for example, a path of a chargefrom the first photoelectric conversion unit on the first transfertransistor to the second photoelectric conversion unit on the secondtransfer transistor can appear.

Furthermore, in the first aspect, the second pixel separation groove maysurround N photoelectric conversion units (N is an integer of two ormore) including the first and second photoelectric conversion units, thesolid-state imaging device may further include a reset, selection, oramplification transistor provided under any photoelectric conversionunit of the N photoelectric conversion units, and the first transfertransistor, the second transfer transistor, and the reset, selection, oramplification transistor may be provided on the surface of the firstsemiconductor substrate on the side opposite to the light incidentsurface. Therefore, for example, the transfer transistors and the otherpixel transistor (reset, selection, or amplification transistor) can besuitably arranged.

Furthermore, the solid-state imaging device of the first aspect mayfurther include a second semiconductor substrate that is provided toface a first interlayer insulating film provided on a surface of thefirst semiconductor substrate on a side opposite to a light incidentsurface, and the second semiconductor substrate may include at least apart of a pixel transistor other than the transfer transistors.Therefore, for example, the pixel transistor can be suitably arranged inthe second semiconductor substrate.

A solid-state imaging device of a second aspect of the presentdisclosure includes: first and second photoelectric conversion unitsthat are provided in the first semiconductor substrate and are adjacentto each other; a floating diffusion unit provided in the firstsemiconductor substrate; and first and second transfer transistorsrespectively provided under the first and second photoelectricconversion units, the first and second transfer transistors operating toprovide: a first mode in which a path of a charge from the firstphotoelectric conversion unit to the floating diffusion unit is closedand a path of a charge from the first photoelectric conversion unit tothe second photoelectric conversion unit is closed; a second mode inwhich the path of the charge from the first photoelectric conversionunit to the floating diffusion unit is closed, and the path of thecharge from the first photoelectric conversion unit to the secondphotoelectric conversion unit is opened; and a third mode in which thepath of the charge from the first photoelectric conversion unit to thefloating diffusion unit is opened. Therefore, for example, a phasedifference can be acquired when a light amount is large by using thefirst mode, the phase difference can be acquired when the light amountis small by using the second mode, and the charge can be transferred tothe floating diffusion unit by using the third mode.

Furthermore, the solid-state imaging device of the second aspect mayfurther include a first pixel separation groove provided between thefirst photoelectric conversion unit and the second photoelectricconversion unit not to penetrate through the first semiconductorsubstrate, and the floating diffusion unit may be provided under thefirst pixel separation groove in the first semiconductor substrate.Therefore, for example, it is possible to obtain the advantage of thenon-through groove by the first pixel separation groove. For example,when the floating diffusion unit is provided under the first pixelseparation groove, the first photoelectric conversion unit and thesecond photoelectric conversion unit can share the floating diffusionunit.

Furthermore, the solid-state imaging device of the second aspect mayfurther include a second pixel separation groove provided to penetratethrough the first semiconductor substrate, and the second pixelseparation groove may be provided to surround at least the first andsecond photoelectric conversion units in a plan view. Therefore, forexample, it is possible to obtain the advantage of the through groove bythe second pixel separation groove. For example, when the second pixelseparation groove is provided to surround the first and secondphotoelectric conversion units in a plan view, the crosstalk between thefirst and second photoelectric conversion units and other photoelectricconversion units can be suppressed by the second pixel separationgroove.

Furthermore, the solid-state imaging device of the second aspect mayfurther include a second semiconductor substrate that is provided toface a first interlayer insulating film provided on a surface of thefirst semiconductor substrate on a side opposite to a light incidentsurface, and the second semiconductor substrate may include at least apart of a pixel transistor other than the transfer transistors.Therefore, for example, the pixel transistor can be suitably arranged inthe second semiconductor substrate.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram illustrating a configuration of a solid-stateimaging device of a first embodiment.

FIG. 2 is a vertical sectional view illustrating a structure of thesolid-state imaging device of the first embodiment.

FIG. 3 is a horizontal sectional view and a vertical sectional viewillustrating the structure of the solid-state imaging device of thefirst embodiment.

FIG. 4 is a horizontal sectional view illustrating the structure of thesolid-state imaging device of the first embodiment.

FIG. 5 is a vertical sectional view and a graph for describing anoperation in a first mode of the solid-state imaging device of the firstembodiment.

FIG. 6 is a vertical sectional view and a graph for describing anoperation in a second mode of the solid-state imaging device of thefirst embodiment.

FIG. 7 is a vertical sectional view and a graph for describing anoperation in a third mode of the solid-state imaging device of the firstembodiment.

FIG. 8 is a horizontal sectional view illustrating a structure of asolid-state imaging device of a second embodiment.

FIG. 9 is a horizontal sectional view illustrating a structure of asolid-state imaging device of a modified example of the secondembodiment.

FIG. 10 is a horizontal sectional view illustrating a structure of asolid-state imaging device of another modified example of the secondembodiment.

FIG. 11 is a horizontal sectional view illustrating a structure of asolid-state imaging device of a third embodiment.

FIG. 12 is a horizontal sectional view illustrating a structure of asolid-state imaging device of a fourth embodiment.

FIG. 13 is a horizontal sectional view illustrating a structure of asolid-state imaging device of a fifth embodiment.

FIG. 14 is a horizontal sectional view illustrating a structure of asolid-state imaging device of a sixth embodiment.

FIG. 15 is a horizontal sectional view illustrating a structure of asolid-state imaging device of a seventh embodiment.

FIG. 16 is a block diagram illustrating a configuration example of anelectronic device.

FIG. 17 is a block diagram illustrating a configuration example of amobile body control system.

FIG. 18 is a plan view depicting a specific example of a settingposition of an imaging unit in FIG. 17 .

FIG. 19 is a diagram illustrating an example of a schematicconfiguration of an endoscopic surgical system.

FIG. 20 is a block diagram illustrating an example of a functionalconfiguration of a camera head and a CCU.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present disclosure will be describedwith reference to the drawings.

First Embodiment

FIG. 1 is a block diagram illustrating a configuration of a solid-stateimaging device of a first embodiment.

The solid-state imaging device in FIG. 1 is a complementary metal oxidesemiconductor (CMOS) type image sensor, and includes a pixel arrayregion 2 having a plurality of pixels 1, a control circuit 3, a verticaldrive circuit 4, a plurality of column signal processing circuits 5, ahorizontal drive circuit 6, an output circuit 7, a plurality of verticalsignal lines 8, and a horizontal signal line 9.

Each of the pixels 1 includes a photodiode functioning as aphotoelectric conversion unit and a MOS transistor functioning as apixel transistor. Examples of the pixel transistor include a transfertransistor, a reset transistor, an amplification transistor, a selectiontransistor, and the like. These pixel transistors may be shared byseveral pixels 1.

The pixel array region 2 includes a plurality of the pixels 1 arrangedin a two-dimensional array. The pixel array region 2 includes aneffective pixel region that receives light, performs photoelectricconversion, amplifies and outputs a signal charge generated by thephotoelectric conversion, and a black reference pixel region thatoutputs optical black serving as a reference of a black level. Ingeneral, the black reference pixel region is arranged on an outerperipheral portion of the effective pixel region.

The control circuit 3 generates various signals serving as references ofoperations of the vertical drive circuit 4, the column signal processingcircuit 5, the horizontal drive circuit 6, and the like on the basis ofa vertical synchronization signal, a horizontal synchronization signal,a master clock, and the like. The signals generated by the controlcircuit 3 are, for example, a clock signal and a control signal, and areinput to the vertical drive circuit 4, the column signal processingcircuit 5, the horizontal drive circuit 6, and the like.

The vertical drive circuit 4 includes, for example, a shift register,and scans each of the pixels 1 in the pixel array region 2 in thevertical direction row by row. Moreover, the vertical drive circuit 4supplies a pixel signal based on the signal charge generated by each ofthe pixels 1 to the column signal processing circuit 5 through thevertical signal line 8.

The column signal processing circuit 5 is arranged, for example, forevery column of the pixels 1 in the pixel array region 2, and performssignal processing of the signals output from the pixels 1 of one row forevery column on the basis of a signal from the black reference pixelregion. Examples of this signal processing are noise removal and signalamplification.

The horizontal drive circuit 6 includes, for example, a shift register,and supplies the pixel signal from each of the column signal processingcircuits 5 to the horizontal signal line 9.

The output circuit 7 performs signal processing on the signal suppliedfrom each of the column signal processing circuits 5 through thehorizontal signal line 9, and outputs the signal subjected to the signalprocessing.

FIG. 2 is a vertical sectional view illustrating a structure of thesolid-state imaging device of the first embodiment. FIG. 2 illustrates avertical section of two pixels 1 included in the pixel array region 2 ofFIG. 1 .

FIG. 2 illustrates an X axis, a Y axis, and a Z axis perpendicular toeach other. An X direction and a Y direction correspond to a lateraldirection (horizontal direction), and a Z direction corresponds to alongitudinal direction (vertical direction). Furthermore, the +Zdirection corresponds to an upward direction, and the −Z directioncorresponds to a downward direction. The −Z direction may strictly matchthe gravity direction, or does not necessarily strictly match thegravity direction.

The solid-state imaging device of the present embodiment includes anupper substrate (first substrate) 11, an intermediate substrate (secondsubstrate) 12, a lower substrate (third substrate) 13, a light shieldingfilm 14, a planarization film 15, a color filter 16, and an on-chip lens17. The on-chip lens 17 is an example of a lens of the presentdisclosure.

The upper substrate 11 includes a first semiconductor substrate 21, afirst interlayer insulating film 22, a gate insulating film 23 and agate electrode 24 of each transistor, an insulating film 25, and aninsulating film 26. The insulating film 25 is an example of a firstinsulating film of the present disclosure, and the insulating film 26 isan example of a second insulating film of the present disclosure. Thefirst semiconductor substrate 21 includes a plurality of n typesemiconductor regions 21 a, a p+ type semiconductor region 21 b, a ptype semiconductor region 21 c, a plurality of n type semiconductorregions 21 d, and a plurality of n type semiconductor regions 21 e.

The intermediate substrate 12 includes a second semiconductor substrate31, a second interlayer insulating film 32, a gate insulating films 33and a gate electrode 34 of each transistor, a plurality of plugs 35, afirst wiring layer 36, a second wiring layer 37, a third wiring layer38, and a third wiring layer 39. The second semiconductor substrate 31includes a plurality of impurity semiconductor regions 31 a. The secondinterlayer insulating film 32 includes an insulating film 32 a and aninsulating film 32 b.

The lower substrate 13 includes a third semiconductor substrate 41, athird interlayer insulating film 42, a gate insulating film 43 and agate electrode 44 of each transistor, a plurality of plugs 45, a fifthwiring layer 46, a wiring layer 47, and a seventh wiring layer 48. Thethird semiconductor substrate 41 includes a plurality of impuritysemiconductor regions 41 a. The third interlayer insulating film 42includes an insulating film 42 a and an insulating film 42 b.

Moreover, the solid-state imaging device of the present embodimentincludes a photodiode PD in each of the pixels 1, a vertical gateelectrode VG in each of the pixels 1, a pixel separation groove T1between the pixels 1, and a pixel separation groove T2 between thepixels 1. The two photodiodes PD illustrated in FIG. 2 are examples offirst and second photoelectric conversion units of the presentdisclosure. The pixel separation groove T1 is an example of a firstpixel separation groove of the present disclosure, and the pixelseparation groove T2 is an example of a second pixel separation grooveof the present disclosure.

Hereinafter, the structure of the solid-state imaging device of thepresent embodiment will be described with reference to FIG. 2 .

The upper substrate 11 is stacked on the intermediate substrate 12. Theintermediate substrate 12 is stacked on the lower substrate 13. FIG. 2illustrates a bonding surface S1 between the upper substrate 11 and theintermediate substrate 12 and a bonding surface S2 between theintermediate substrate 12 and the lower substrate 13. The lightshielding film 14, the planarization film 15, the color filter 16, andthe on-chip lens 17 are sequentially formed on the upper substrate 11.Details of the light shielding film 14, the planarization film 15, thecolor filter 16, and the on-chip lens 17 will be described later.

The first semiconductor substrate 21 is, for example, a siliconsubstrate. In FIG. 2 , a surface (lower surface) of the firstsemiconductor substrate 21 in the −Z direction is a front surface of thefirst semiconductor substrate 21, and a surface (upper surface) of thefirst semiconductor substrate 21 in the +Z direction is a back surfaceof the first semiconductor substrate 21. Since the solid-state imagingdevice of the present embodiment is of a back-illuminated type, the backsurface of the first semiconductor substrate 21 is a light incidentsurface (light reception surface) of the first semiconductor substrate21.

The first semiconductor substrate 21 includes an impurity semiconductorregion such as the n type semiconductor region 21 a. The p+ typesemiconductor region 21 b is provided around the n type semiconductorregion 21 a. The p type semiconductor region 21 c is provided under thep+ type semiconductor region 21 b. The n type semiconductor region 21 dand the n type semiconductor region 21 e are provided under the p typesemiconductor region 21 c.

The photodiode PD is provided for each of the pixels 1 in the firstsemiconductor substrate 21. Each of the photodiodes PD is formed by a pnjunction or the like between the n type semiconductor region 21 a andthe p+ type semiconductor region 21 b. Each of the photodiodes PDfunctions as the photoelectric conversion unit that converts light intoa charge. Specifically, each of the photodiodes PD receives light fromthe back surface of the first semiconductor substrate 21, generates asignal charge corresponding to the amount of the received light, andaccumulates the generated signal charge in the n type semiconductorregion 21 a.

The first interlayer insulating film 22 is provided on a surface on theopposite side of the light incident surface of the first semiconductorsubstrate 21. Examples of the first interlayer insulating film 22include a silicon oxide film and a laminated film including a siliconoxide film and other insulating films.

The gate insulating film 23 and the gate electrode 24 of each transistorin the upper substrate 11 are sequentially provided under the firstsemiconductor substrate 21. FIG. 2 illustrates the gate insulating films23 and the gate electrodes 24 of two transistors. These transistors are,for example, transfer transistors. The gate insulating film 23 and thegate electrode 24 include a portion that is provided outside the firstsemiconductor substrate 21 and covered with the first interlayerinsulating film 22, and a portion provided in the first semiconductorsubstrate 21. The gate electrode 24 in the first semiconductor substrate21 is referred to as the vertical gate electrode VG. The vertical gateelectrode VG is provided in the p type semiconductor region 21 c, the p+type semiconductor region 21 b, and the n type semiconductor region 21a. These transistors are examples of first and second transfertransistors of the present disclosure.

The insulating film 25 is embedded in the pixel separation groove T1provided in the first semiconductor substrate 21. Therefore, thephotodiodes PD can be separated from each other by the insulating film25. Examples of the insulating film 25 include a silicon oxide film anda laminated film including a silicon oxide film and other insulatingfilms. Here, it is assumed that a groove (trench) for a semiconductorsubstrate is provided even in a case where the pixel separation grooveis filled with a material different from the semiconductor substrate.

The pixel separation groove T1 is a non-through groove provided betweenthe photodiodes PD so as not to penetrate through the firstsemiconductor substrate 21. The pixel separation groove T1 is providedon the back surface (upper surface) of the first semiconductor substrate21, and does not reach the front surface (lower surface) of the firstsemiconductor substrate 21. As described later, the pixel separationgroove T1 of the present embodiment is provided among four photodiodesPD adjacent to each other, and has a cross shape in a plan view (seeFIG. 4 ). The pixel separation groove T1 illustrated in FIG. 2 isprovided between the two photodiodes PD illustrated in FIG. 2 . Thepixel separation groove T1 includes only the insulating film 25 in thepresent embodiment, but may further include a light shielding film inthe insulating film 25.

The insulating film 26 is embedded in the pixel separation groove T2provided in the first semiconductor substrate 21. Therefore, thephotodiodes PD can be separated from each other by the insulating film26. Examples of the insulating film 26 include a silicon oxide film anda laminated film including a silicon oxide film and other insulatingfilms.

The pixel separation groove T2 is a through groove provided between thephotodiodes PD so as to penetrate through the first semiconductorsubstrate 21. The pixel separation groove T2 penetrates between thefront surface (upper surface) and the back surface (lower surface) ofthe first semiconductor substrate 21. As described later, the pixelseparation groove T2 of the present embodiment has a shape thatsurrounds the plurality of photodiodes PD in the first semiconductorsubstrate 21 for every four photodiodes PD in a plan view (see FIG. 4 ).Therefore, the pixel separation groove T1 and the pixel separationgroove T2 of the present embodiment form a pixel separation groove thatsurrounds the plurality of photodiodes PD in the first semiconductorsubstrate 21 in a plan view for each of the photodiodes PD (see FIG. 4). The pixel separation groove T2 illustrated in FIG. 2 surrounds thetwo photodiodes PD illustrated in FIG. 2 in a plan view. Note that thenumber N (N is an integer of two or more) of photodiodes PD surroundedby the pixel separation groove T2 may be other than four. The pixelseparation groove T2 includes only the insulating film 26 in the presentembodiment, but may further include a light shielding film in theinsulating film 26.

The second semiconductor substrate 31 is, for example, a siliconsubstrate. In FIG. 2 , a surface (lower surface) of the secondsemiconductor substrate 31 in the −Z direction is a front surface of thesecond semiconductor substrate 31, and a surface (upper surface) of thesecond semiconductor substrate 31 in the +Z direction is a back surfaceof the second semiconductor substrate 31. The second semiconductorsubstrate 31 of the present embodiment is provided under the firstinterlayer insulating film 22 in a state where the upper surface of thesecond semiconductor substrate 31 is bonded to the lower surface of thefirst interlayer insulating film 22.

The second interlayer insulating film 32 includes the insulating film 32a provided under the second semiconductor substrate 31 and theinsulating film 32 b provided under the insulating film 32 a. Examplesof the insulating film 32 a include a silicon oxide film and a laminatedfilm including a silicon oxide film and other insulating films.Similarly, examples of the insulating film 32 b is a silicon oxide filmor a laminated film including a silicon oxide film and other insulatingfilms.

The gate insulating film 33 and the gate electrode 34 of each transistorin the intermediate substrate 12 are sequentially provided under thesecond semiconductor substrate 31. FIG. 2 illustrates the gateinsulating films 33 and the gate electrodes 34 of two transistors. Thesetransistors are, for example, pixel transistors other than the transfertransistors. The gate insulating film 33 and the gate electrode 34 areprovided outside the second semiconductor substrate 31 and covered withthe second interlayer insulating film 32. The impurity semiconductorregions 31 a in the second semiconductor substrate 31 function as, forexample, a source region and a drain region of these transistors.

The plugs 35, the first wiring layer 36, the second wiring layer 37, thethird wiring layer 38, and the third wiring layer 39 are provided in thesecond interlayer insulating film 32. The plugs 35 are provided betweenthe second semiconductor substrate 31 and the first wiring layer 36,between the gate electrode 33 and the first wiring layer 36, between thefirst wiring layer 36 and the second wiring layer 37, between the secondwiring layer 37 and the third wiring layer 38, and between the thirdwiring layer 38 and the third wiring layer 39, respectively. The firstwiring layers 36 to 39 form a first multilayer wiring in the secondinterlayer insulating film 32. Furthermore, the number of layers of thefirst multilayer wiring is not limited thereto. Moreover, FIG. 2illustrates two plugs 35 provided between the first wiring layer 36 andthe first semiconductor substrate 21 (n type semiconductor region 21 e)in the second interlayer insulating films 32 and 22. Therefore, theupper substrate 11 and the intermediate substrate 12 are electricallyconnected.

The third semiconductor substrate 41 is, for example, a siliconsubstrate. In FIG. 2 , a surface (upper surface) of the thirdsemiconductor substrate 41 in the +Z direction is a front surface of thethird semiconductor substrate 41, and a surface (lower surface) of thethird semiconductor substrate 41 in the −Z direction is a back surfaceof the third semiconductor substrate 41.

The third interlayer insulating film 42 includes the insulating film 42a provided on the third semiconductor substrate 41 and the insulatingfilm 42 b provided on the insulating film 42 a. Examples of theinsulating film 42 a include a silicon oxide film and a laminated filmincluding a silicon oxide film and other insulating films. Similarly,examples of the insulating film 42 b is a silicon oxide film or alaminated film including a silicon oxide film and other insulatingfilms. The insulating film 42 b of the present embodiment is providedunder the insulating film 32 b in a state where the upper surface of theinsulating film 42 b is bonded to the lower surface of the insulatingfilm 32 b.

The gate insulating film 43 and the gate electrode 44 of each transistorin the lower substrate 13 are sequentially provided on the thirdsemiconductor substrate 41. FIG. 2 illustrates the gate insulating films43 and the gate electrodes 44 of two transistors. These transistors are,for example, pixel transistors other than the transfer transistors. Thegate insulating film 43 and the gate electrode 44 are provided outsidethe third semiconductor substrate 41 and covered with the thirdinterlayer insulating film 42. The impurity semiconductor regions 41 ain the third semiconductor substrate 41 function as, for example, asource region and a drain region of these transistors.

The plugs 45, the fifth wiring layer 46, the sixth wiring layer 47, andthe seventh wiring layer 48 are provided in the third interlayerinsulating film 42. The plugs 45 are provided between the thirdsemiconductor substrate 41 and the fifth wiring layer 46, between thegate electrode 43 and the fifth wiring layer 46, between the fifthwiring layer 46 and the sixth wiring layer 47, and between the sixthwiring layer 47 and the seventh wiring layer 48, respectively. The fifthto seventh wiring layers 46 to 48 form a second multilayer wiring in thethird interlayer insulating film 42. Furthermore, the number of layersof the second multilayer wiring is not limited thereto. The seventhwiring layer 48 of the present embodiment is provided under the thirdwiring layer 39 in a state where an upper surface of the seventh wiringlayer 48 is bonded to the lower surface of the third wiring layer 39.Therefore, the intermediate substrate 12 and the lower substrate 13 areelectrically connected.

The light shielding film 14 has an action of shielding light, and isformed on upper surfaces of the insulating films 25 and 26. The lightshielding film 14 is, for example, a film containing a metal elementsuch as tungsten (W), aluminum (Al), or copper (Cu).

The planarization film 15 is formed on the first semiconductor substrate21 with the light shielding film 14 interposed therebetween, whereby asurface above the back surface of the first semiconductor substrate 21is flat. The planarization film 15 is, for example, an organic film suchas a resin film.

The color filter 16 has an action of transmitting light having apredetermined wavelength, and is formed on the planarization film 15 forevery predetermined number of the pixels 1. For example, the colorfilters 16 for red (R), green (G), and blue (B) are arranged above thephotodiodes PD of the red, green, and blue pixels 1, respectively.Moreover, the color filter 16 for infrared light (IR) may be arrangedabove the photodiode PD of the pixel 1 for infrared light. The lighttransmitted through the color filter 16 is incident on the photodiode PDvia the planarization film 15. The color filter 16 of the presentembodiment is formed for every four pixels 1 on the planarization film15, and the color filters 16 and the pixels 1 have a one-to-fourcorrespondence.

The on-chip lens 17 has an action of collecting light, and is formed onthe color filter 16 for every predetermined number of pixels 1. Thelight collected by the on-chip lens 17 is incident on the photodiode PDvia the color filter 16 and the planarization film 15. The on-chip lens17 of the present embodiment is formed for every four pixels 1 on thecolor filter 16, and the on-chip lenses 17 and the pixels 1 have aone-to-four correspondence.

In the present embodiment, light incident on the on-chip lens 17 iscollected by the on-chip lens 17, transmitted through the color filter16, and incident on the photodiode PD. The photodiode PD converts thelight into a charge by photoelectric conversion to generate a signalcharge. The signal charge is output as a pixel signal via the verticalsignal line 8 (FIG. 1 ) in the first to seventh wiring layers 36 to 39and 46 to 48.

FIG. 3 is a horizontal sectional view and a vertical sectional viewillustrating the structure of the solid-state imaging device of thefirst embodiment.

A horizontal section of four pixels 1 included in the pixel array region2 of FIG. 1 is illustrated in A of FIG. 3 , and vertical sections of twopixels 1 included in the pixel array region 2 of FIG. 1 are illustratedin B and C of FIG. 3 , respectively. A line A-A′ extending in the Xdirection, a line B-B′ extending in the X direction, and a line C-C′extending in a direction inclined with respect to the X direction areillustrated in A of FIG. 3 . FIG. 2 , B of FIG. 3 , and C of FIG. 3illustrate sections taken along the lines B-B′, B-B′, and C-C′illustrated in A of FIG. 3 , respectively. The same XZ section as the XZsection of FIG. 2 is illustrated in B of FIG. 3 in a simplified manner,and the vertical section inclined with respect to the XZ section isillustrated in C of FIG. 3 .

A section of the first semiconductor substrate 21, specifically, asection of the photodiodes PD in the four pixels 1 is illustrated in Aof FIG. 3 . The pixel separation grooves T1 and T2, the insulating films25 and 26, and the four vertical gate electrodes VG provided in thefirst semiconductor substrate 21 are illustrated in A of FIG. 3 .Moreover, for convenience, the on-chip lens 17 provided on the firstsemiconductor substrate 21, a floating diffusion unit FD provided underthe pixel separation groove T1 in the first semiconductor substrate 21,and a p+ type region around the floating diffusion unit FD areillustrated in A of FIG. 3 in order to facilitate the understanding ofthe description. Moreover, for convenience, A of FIG. 3 illustratestriangular planar shapes of four transfer transistors, which areprovided under the first semiconductor substrate 21 and include thevertical gate electrodes VG around the vertical gate electrode VG, inorder to facilitate the understanding of the description. Referencesigns TGL and TGR illustrated in A of FIG. 3 indicate an upper lefttransfer transistor and an upper right transfer transistor,respectively, of the four transfer transistors. The transfer transistorsTGL and TGR are examples of the first and second transfer transistors,respectively. The floating diffusion unit FD is provided in the firstsemiconductor substrate 21 at a position at least partially overlappingthe pixel separation groove T1 in a plan view.

The four pixels 1 illustrated in A of FIG. 3 are pixels of the samecolor. For example, all of the four pixels 1 illustrated in A of FIG. 3are red (R) pixels. Thus, one on-chip lens 17 is provided on thephotodiodes PD of these pixels 1, and these pixels 1 share this on-chiplens 17. Similarly, one color filter 16 is provided on the photodiodesPD of these pixels 1, and these pixels 1 share this color filter 16.

In A of FIG. 3 , the pixel separation groove T1 is provided among thefour photodiodes PD of the pixels 1, and has a cross shape in a planview. On the other hand, the pixel separation groove T2 has a shapesurrounding the four photodiodes PD. Therefore, the pixel separationgroove T1 and the pixel separation groove T2 form the pixel separationgroove surrounding the four photodiodes PD for each of the photodiodesPD.

Note that the pixel separation groove T1 illustrated in A of FIG. 3seems to be divided into four since the floating diffusion unit FD andthe p+ type region are illustrated in A of FIG. 3 , but it should benoted that the pixel separation groove T1 has a cross shape illustratedin FIG. 4 to be precise. The shape of the pixel separation groove T1 ofthe present embodiment is the same in both the section along the lineB-B′ and the section along the line A-A′.

The pixel separation groove T1 has a cross planar shape, and thus,includes a first portion extending in the X direction and a secondportion extending in the Y direction, and the floating diffusion unit FDis provided under an intersection portion between the first portion andthe second portion in the first semiconductor substrate 21 (see C ofFIG. 3 ). The X direction and the Y direction are examples of first andsecond directions of the present disclosure, respectively. The floatingdiffusion unit FD of the present embodiment is shared by the four pixels1 illustrated in A of FIG. 3 .

The floating diffusion unit FD is, for example, an n+ type semiconductorregion provided under the p type semiconductor region 21 c in the firstsemiconductor substrate 21. In A of FIG. 3 , the floating diffusion unitFD is used to accumulate the signal charge generated by the each of thephotodiodes PD illustrated in A of FIG. 3 . Furthermore, each of thetransfer transistors illustrated in FIG. 3 has a function oftransferring the signal charge from the photodiode PD located on thetransfer transistor to the floating diffusion unit FD.

The signal charge can also be transferred and received between the twophotodiodes PD illustrated in A of FIG. 3 . For example, the transfertransistors TGL and TGR can perform transfer of the signal chargegenerated by the photodiode PD located on the transfer transistor TGL tothe photodiode PD located on the transfer transistor TGR via a regionunder the pixel separation groove T1 in the first semiconductorsubstrate 21 (see B of FIG. 3 ). Note that further details of thetransfer of the signal charge will be described later.

Two photodiodes PD and the vertical gate electrodes VG of the twotransfer transistors under these photodiodes PD are illustrated in B ofFIG. 3 . The left and right transfer transistors illustrated in B ofFIG. 3 are the above-described transfer transistors TGL and TGR,respectively. The pixel separation groove T1 between these photodiodesPD is the non-through groove. Therefore, the transfer transistors TGLand TGR can perform transfer of the signal charge generated by thephotodiode PD located on the transfer transistor TGL to the photodiodePD located on the transfer transistor TGR via a region under the pixelseparation groove T1 in the first semiconductor substrate 21. Arrowsillustrated in B of FIG. 3 indicate such transfer of the signal charge.

The solid-state imaging device of the present embodiment can operate toobtain a high dynamic range by making signal charge accumulation timesdifferent among the four pixels 1 (pixels of the same color) illustratedin A of FIG. 3 . In this case, if the pixel separation groove amongthese pixels 1 is not a through groove but a non-through groove, thesignal charge moves (overflows) among the pixels 1, and thus, there is apossibility that it is difficult to obtain the high dynamic range. Sincethe pixel separation groove among these pixels 1 of the presentembodiment is the pixel separation groove T1 which is the non-throughgroove, such a problem may occur.

On the other hand, if the pixel separation groove among these pixels 1of the present embodiment is formed as a through groove, it becomesdifficult to obtain an advantage of the overflow of the signal charge.Specifically, if it is difficult for the signal charge to move(overflow) among these pixels 1, linearity collapses at an end of thepixel 1, and a point defect occurs.

Therefore, the pixel separation groove among the four pixels 1illustrated in A of FIG. 3 is the pixel separation groove T1 which isthe non-through groove in the present embodiment. Therefore, the signalcharge can move (overflow) among these pixels 1, it is possible tosuppress the collapse of the linearity at the end of the pixel 1, and itis possible to suppress the occurrence of the point defect. On the otherhand, the problem that it is difficult to obtain the high dynamic rangedue to the overflow of the signal charge can be suppressed by, forexample, making the pixel separation groove T1 sufficiently deep orclosing an overflow path by the operation of the transfer transistor.Therefore, it is possible to widen a light amount range in which a phasedifference can be acquired. In this manner, it is possible to obtainboth an advantage of the through groove and an advantage of thenon-through groove according to the present embodiment. Note thatfurther details of the closing of the overflow path will be describedlater.

FIG. 4 is a horizontal sectional view illustrating a structure of thesolid-state imaging device of the first embodiment.

FIG. 4 illustrates the same XY section as the XY section in A of FIG. 3. However, A of FIG. 3 illustrates four pixels 1 included in the pixelarray region 2 of FIG. 1 , whereas FIG. 4 illustrates sixteen pixels 1included in the pixel array region 2 of FIG. 1 .

The sixteen pixels 1 illustrated in FIG. 4 include four red (R) pixels,four green (G) pixels, four blue (B) pixels, and four infrared light(IR) pixels. The pixel separation groove T2 surrounds the photodiodes PDof the pixels 1 for every four photodiodes PD in a plan view.Specifically, the pixel separation groove T2 illustrated in FIG. 4includes a portion surrounding the photodiodes PD of the four redpixels, a portion surrounding the photodiodes PD of the four greenpixels, a portion surrounding the photodiodes PD of the four bluepixels, and a portion surrounding the photodiodes PD of the fourinfrared light pixels. Thus, these photodiodes PD are surrounded forevery pixel of the same color. The four pixels 1 of each color have thestructure described with reference to A of FIG. 3 .

In the present embodiment, the pixels 1 of different colors areseparated by the pixel separation groove T2 (through groove), crosstalkbetween these pixels 1 can be effectively suppressed.

Next, three operation modes of the solid-state imaging device of thepresent embodiment will be described with reference to FIGS. 5 to 7 .

FIG. 5 is a vertical sectional view and a graph for describing anoperation in a first mode of the solid-state imaging device of the firstembodiment.

A section taken along the line B-B′ similarly to B of FIG. 3 isillustrated in A of FIG. 5 , and a section taken along the line C-C′similarly to C of FIG. 3 is illustrated in B of FIG. 5 . Furthermore, Cof FIG. 5 illustrates a profile of potentials in a section taken alongthe line B-B′, and D of FIG. 5 illustrates a profile of potentials in asection taken along the line C-C′.

The transfer transistors TGL and TGR in the first mode operate to closea charge path from the photodiode PD located on the transfer transistorTGL to the photodiode PD located on the transfer transistor TGR (A ofFIG. 5 ). Therefore, it is possible to suppress the overflow of thesignal charge between these photodiodes PD. Moreover, the transfertransistor TGL in the first mode further operates to close a charge pathfrom the photodiode PD located on the transfer transistor TGL to thefloating diffusion unit FD (B of FIG. 5 ).

In the first mode, potentials at positions of the transfer transistorsTGL and TGR are set high (C and D in FIG. 5 ). Therefore, it is possibleto suppress the signal charge (Qs) from moving between the photodiode PDon the transfer transistor TGL and the photodiode PD on the transfertransistor TGR (C of FIG. 5 ). Moreover, it is possible to suppress thesignal charge from moving from the photodiode PD on the transfertransistor TGL to the floating diffusion unit FD (D of FIG. 5 ).

According to the first mode, it is possible to achieve the operationsimilar to that in the case where the pixel separation groove T1 isreplaced with a through groove. The first mode can be used, for example,in a case where it is desired to widen the light amount range in whichthe phase difference can be acquired. According to the first mode, forexample, the phase difference can be acquired when the light amount islarge.

FIG. 6 is a vertical sectional view and a graph for describing anoperation in a second mode of the solid-state imaging device of thefirst embodiment.

A section taken along the line B-B′ similarly to B of FIG. 3 isillustrated in A of FIG. 6 , and a section taken along the line C-C′similarly to C of FIG. 3 is illustrated in B of FIG. 6 . Furthermore, Cof FIG. 6 illustrates a profile of potentials in a section taken alongthe line B-B′, and D of FIG. 6 illustrates a profile of potentials in asection taken along the line C-C′.

The transfer transistors TGL and TGR in the second mode operate to openthe charge path from the photodiode PD located on the transfertransistor TGL to the photodiode PD located on the transfer transistorTGR (A of FIG. 6 ). Therefore, it is possible to make the signal chargeoverflow between these photodiodes PD. Moreover, the transfer transistorTGL in the second mode further operates to close the charge path fromthe photodiode PD located on the transfer transistor TGL to the floatingdiffusion unit FD (B of FIG. 6 ).

In the second mode, potentials at the positions of the transfertransistors TGL and TGR are set lower than those in the first mode (Cand D in FIG. 6 ). Therefore, it is possible to make the signal chargemove between the photodiode PD on the transfer transistor TGL and thephotodiode PD on the transfer transistor TGR (C of FIG. 6 ). Moreover,it is possible to suppress the signal charge from moving from thephotodiode PD on the transfer transistor TGL to the floating diffusionunit FD (D of FIG. 6 ).

According to the second mode, it is possible to cause the overflow ofthe signal charge via a region under the pixel separation groove T1which is the non-through groove. Therefore, it is possible to suppressthe occurrence of the linearity collapse at the end of the pixel 1, andit is possible to suppress the occurrence of the point defect. Accordingto the second mode, for example, the phase difference can be acquiredwhen the light amount is small.

FIG. 7 is a vertical sectional view and a graph for describing anoperation in a third mode of the solid-state imaging device of the firstembodiment.

A section taken along the line B-B′ similarly to B of FIG. 3 isillustrated in A of FIG. 7 , and a section taken along the line C-C′similarly to C of FIG. 3 is illustrated in B of FIG. 7 . Furthermore, Cof FIG. 7 illustrates a profile of potentials in a section taken alongthe line B-B′, and D of FIG. 7 illustrates a profile of potentials in asection taken along the line C-C′.

The transfer transistors TGL and TGR in the third mode operate to closea charge path from the photodiode PD located on the transfer transistorTGL to the photodiode PD located on the transfer transistor TGR (A ofFIG. 7 ). Therefore, it is possible to suppress the overflow of thesignal charge between these photodiodes PD. Moreover, the transfertransistor TGL in the third mode further operates to open the chargepath from the photodiode PD located on the transfer transistor TGL tothe floating diffusion unit FD (B of FIG. 7 ). Therefore, the signalcharge generated by the photodiode PD can be accumulated in the floatingdiffusion unit FD.

In the first mode and the second mode, the potentials at the positionsof the transfer transistors TGL and TGR are set higher than potentialsat positions of the photodiode PD thereon (C and D in FIG. 5 and C and Din FIG. 6 ). On the other hand, in the third mode, the potential at theposition of the transfer transistor TGL is set lower than the potentialat the position of the photodiode PD, and the potential at the positionof the transfer transistor TGR is set higher than the potential at theposition of the photodiode PD (C and D in FIG. 7 ). Therefore, it ispossible to suppress the signal charge from moving between thephotodiode PD on the transfer transistor TGL and the photodiode PD onthe transfer transistor TGR (C of FIG. 7 ). Moreover, it is possible tomake the signal charge move from the photodiode PD on the transfertransistor TGL to the floating diffusion unit FD (D of FIG. 7 ).

According to the third mode, it is possible to transfer the signalcharge from the photodiode PD to the floating diffusion unit FD via theregion under the pixel separation groove T1 which is the non-throughgroove.

Note that the contents described with reference to A and C of FIG. 5 , Aand C of FIG. 6 , and A and C of FIG. 7 are also applicable to the pairof two transfer transistors other than the pair of transfer transistorsTGL and TRG among the four transfer transistors illustrated in A of FIG.3 .

Furthermore, the contents described with reference to B and D of FIG. 5, B and D of FIG. 6 , and B and D of FIG. 7 are also applicable to thetransfer transistors other than the transfer transistor TGL among thefour transfer transistors illustrated in A of FIG. 3 .

As described above, the pixel separation groove in the firstsemiconductor substrate 21 of the present embodiment includes the pixelseparation groove T1 which is the non-through groove and the pixelseparation groove T2 which is the through groove. Thus, it is possibleto form the pixel separation groove having a suitable action in thefirst semiconductor substrate 21 according to the present embodiment.For example, the advantage of the non-through groove can be obtained bythe pixel separation groove T1, and the advantage of the through groovecan be obtained by the pixel separation groove T2. Furthermore, when thecontrol as illustrated in FIGS. 5 to 7 , for example, is adopted, it ispossible to obtain an effect obtained as the pixel separation groove T1is the non-through groove and an effect similar to that in the casewhere the pixel separation groove T1 is replaced with the throughgroove.

Second Embodiment

FIG. 8 is a horizontal sectional view illustrating a structure of asolid-state imaging device of a second embodiment.

FIG. 8 illustrates a horizontal section of four pixels 1 similarly to Aof FIG. 3 . These pixels 1 are, for example, pixels of the same color.The solid-state imaging device in FIG. 8 has substantially the samestructure as the solid-state imaging device in A of FIG. 3 . However,four photodiodes PD illustrated in FIG. 8 are provided under two on-chiplenses 17 extending in the X direction, and the on-chip lenses 17 andthe photodiodes PD have a one-to-two correspondence. Note that colorfilters 16 and the photodiodes PD of the present embodiment may have aone-to-two correspondence, or may have a one-to-four correspondence.

According to the present embodiment, it is possible to arrange a largernumber of smaller on-chip lenses 17 as compared with the firstembodiment, and thus, it is possible to finely control an optical pathby the on-chip lenses 17, for example. On the other hand, according tothe first embodiment, the on-chip lens 17 can be easily formed, forexample, as compared with the present embodiment.

FIG. 9 is a horizontal sectional view illustrating a structure of asolid-state imaging device of a modified example of the secondembodiment.

FIG. 9 also illustrates a horizontal section of four pixels 1. Fourphotodiodes PD illustrated in FIG. 9 are provided under two on-chiplenses 17 extending in the Y direction, and the on-chip lenses 17 andthe photodiodes PD have a one-to-two correspondence. In this manner, theon-chip lens 17 of the present embodiment may extend in the X directionor the Y direction.

FIG. 10 is a horizontal sectional view illustrating a structure of asolid-state imaging device of another modified example of the secondembodiment.

FIG. 10 illustrates a horizontal section of sixteen pixels 1 similarlyto FIG. 4 . In the solid-state imaging device in FIG. 10 as well, theon-chip lenses 17 and the photodiodes PD have a one-to-twocorrespondence. However, the solid-state imaging device in FIG. 10includes both the on-chip lens 17 extending in the X direction and theon-chip lens 17 extending in the Y direction. In this manner, theon-chip lenses 17 of the present embodiment may include the on-chip lens17 extending in the X direction and the on-chip lens 17 extending in theY direction.

Third Embodiment

FIG. 11 is a horizontal sectional view illustrating a structure of asolid-state imaging device of a third embodiment.

FIG. 11 illustrates a horizontal section of four pixels 1 similarly to Aof FIG. 3 and the like. These pixels 1 are, for example, pixels of thesame color. The solid-state imaging device in FIG. 11 has substantiallythe same structure as the solid-state imaging device in A of FIG. 3 .However, a pixel separation groove T2 illustrated in FIG. 11 not onlysurrounds four photodiodes PD in a plan view, but also is provided amongthese photodiodes PD together with a pixel separation groove T1. Thus,the photodiodes PD illustrated in FIG. 11 are separated from each otherby the pixel separation groove T1 and the pixel separation groove T2.

According to the present embodiment, a proportion of a through groove(the pixel separation groove T2) to the entire pixel separation groovecan be increased, and thus, it is possible to more strongly obtain anadvantage of the through groove, for example. On the other hand,according to the first embodiment, the pixel separation groove T1 andthe pixel separation groove T2 can be prevented from being mixed betweenthe same color pixels, and thus, the pixel separation grooves T1 and T2can be easily formed, for example.

Fourth Embodiment

FIG. 12 is a horizontal sectional view illustrating a structure of asolid-state imaging device of a fourth embodiment.

FIG. 12 illustrates a horizontal section of four pixels 1 similarly to Aof FIG. 3 and the like. These pixels 1 are, for example, pixels of thesame color. The solid-state imaging device in FIG. 12 has substantiallythe same structure as the solid-state imaging device in A of FIG. 3 .However, the solid-state imaging device in FIG. 12 includes not onlytransfer transistors such as TGL and TGR but also a reset transistorRST, a selection transistor SEL, and an amplification transistor AMP ona front surface (lower surface) of a first semiconductor substrate 21.That is, all of these transistors are provided on the surface oppositeto a light incident surface of the first semiconductor substrate 21. Inthis manner, the reset transistor RST, the selection transistor SEL, andthe amplification transistor AMP of the present embodiment may beprovided in an upper substrate 11 instead of being provided in a lowersubstrate 13 or an intermediate substrate 12 (see FIG. 2 ). Note thatthe solid-state imaging device of the present embodiment does notnecessarily include at least one of the lower substrate 13 or theintermediate substrate 12.

Fifth Embodiment

FIG. 13 is a horizontal sectional view illustrating a structure of asolid-state imaging device of a fifth embodiment.

FIG. 13 also illustrates a horizontal section of eight pixels 1. In thesolid-state imaging device illustrated in FIG. 13 , on-chip lenses 17and photodiodes PD have a one-to-two correspondence similarly to thesolid-state imaging device illustrated in FIG. 8 . However, in thesolid-state imaging device illustrated in FIG. 13 , a planar shape ofthe on-chip lens 17 is a circle, and a planar shape of the photodiode PDis a rectangle. Note that the eight pixels 1 illustrated in FIG. 13 mayinclude eight pixels of the same color, or may include four pixels of acertain color and four pixels of another color.

According to the present embodiment, the solid-state imaging devicehaving a structure similar to that of the solid-state imaging device ofthe second embodiment can be achieved by elongating the planar shape ofthe photodiode PD instead of elongating the planar shape of the on-chiplens 17. Note that the planar shape of the photodiode PD of the presentembodiment may be a rectangle extending in the Y direction or arectangle extending in the X direction.

Sixth Embodiment

FIG. 14 is a horizontal sectional view illustrating a structure of asolid-state imaging device of a sixth embodiment.

FIG. 14 also illustrates a horizontal section of nine pixels 1. Thesepixels 1 are, for example, pixels of the same color. A pixel separationgroove T2 illustrated in FIG. 14 has a shape that surrounds a pluralityof photodiodes PD in a first semiconductor substrate 21 for every ninephotodiodes PD in a plan view. On the other hand, a pixel separationgroove T1 illustrated in FIG. 14 is provided among these ninephotodiodes PD. Thus, the pixel separation groove T1 and the pixelseparation groove T2 illustrated in FIG. 14 form a pixel separationgroove that surrounds the photodiodes PD in a plan view for each of thephotodiodes PD.

The nine photodiodes PD illustrated in FIG. 14 are provided under nineon-chip lenses 17, and the on-chip lenses 17 and the photodiodes PD havea one-to-one correspondence. According to the present embodiment, it ispossible to arrange a large number of small on-chip lenses 17 similarlyto the second embodiment, and thus, it is possible to finely control anoptical path by the on-chip lenses 17, for example. Note that colorfilters 16 and the photodiodes PD of the present embodiment may have aone-to-one correspondence, or may have a one-to-nine correspondence.

The solid-state imaging device of the present embodiment includes thephotodiodes PD surrounded by the pixel separation grooves T2 in units of3×3 (=9), but may include photodiodes PD surrounded by the pixelseparation grooves T2 in units of K×K (K is an integer of four or more)instead.

Seventh Embodiment

FIG. 15 is a horizontal sectional view illustrating a structure of asolid-state imaging device of a seventh embodiment.

FIG. 15 also illustrates a horizontal section of four pixels 1. Thesepixels 1 are, for example, pixels of the same color. The solid-stateimaging device in FIG. 15 has substantially the same structure as thesolid-state imaging device in A of FIG. 3 . However, pixel separationgrooves T1 and T2 illustrated in FIG. 15 extend in an X′ direction and aY′ direction while the pixel separation grooves T1 and T2 illustrated inA of FIG. 3 extend in the X direction and the Y direction. The X′direction is inclined by a predetermined angle with respect to the Xdirection, and the Y′ direction is also inclined by the predeterminedangle with respect to the Y direction. Thus, the pixel 1 of thesolid-state imaging device in FIG. 15 has a structure obtained byinclining the pixel 1 of the solid-state imaging device in A of FIG. 3by the predetermined angle. The predetermined angle is, for example, 45degrees. The X′ direction and the Y′ direction are examples of the firstand second directions of the present disclosure, respectively.

Here, an example of the structure of the solid-state imaging device in Aof FIG. 3 and the structure of the solid-state imaging device in FIG. 15will be described.

In this example, a planar shape of a semiconductor chip including thesolid-state imaging device in A of FIG. 3 is a rectangle having twosides extending in the X direction and two sides extending in the Ydirection. Similarly, a planar shape of a semiconductor chip includingthe solid-state imaging device in FIG. 15 is also a rectangle having twosides extending in the X direction and two sides extending in the Ydirection. Thus, each of these semiconductor chips has two end surfacesextending in the X direction and two end surfaces extending in the Ydirection.

Here, in the solid-state imaging device in A of FIG. 3 , the pixelseparation grooves T1 and T2 also extend in the X direction and the Ydirection. Thus, the pixel separation grooves T1 and T2 illustrated in Aof FIG. 3 extend in a direction parallel to the end surface of thesemiconductor chip or in a direction perpendicular to the end surface ofthe semiconductor chip.

On the other hand, in the solid-state imaging device of FIG. 15 , thepixel separation grooves T1 and T2 extend in the X′ direction and the Y′direction. Thus, the pixel separation grooves T1 and T2 illustrated inFIG. 15 extend in a direction non-parallel and non-perpendicular to theend surfaces of the semiconductor chip. Such a structure is adopted, forexample, in a case where it is desirable to set a channel direction of apixel transistor to be a direction different from both the X directionand the Y direction. Specifically, it is considered that it is sometimesdesired to set the channel direction of the pixel transistor to adirection different from both the X direction and the Y direction in acase where a front surface of a wafer (first semiconductor substrate 21)for a photodiode PD is not a plane {100} or in a case where a directionfrom the center of the wafer toward a notch is not a direction <100>.

Application Examples

FIG. 16 is a block diagram illustrating a configuration example of anelectronic device. The electronic device illustrated in FIG. 16 is acamera 100.

The camera 100 includes an optical unit 101 including a lens group andthe like, an imaging device 102 that is the solid-state imaging deviceaccording to any of the first to seventh embodiments, a digital signalprocessor (DSP) circuit 103 that is a camera signal processing circuit,a frame memory 104, a display unit 105, a recording unit 106, anoperation unit 107, and a power supply unit 108. Furthermore, the DSPcircuit 103, the frame memory 104, the display unit 105, the recordingunit 106, the operation unit 107, and the power supply unit 108 areconnected to each other via a bus line 109.

The optical unit 101 captures incident light (image light) from asubject and forms an image on an imaging surface of the imaging device102. The imaging device 102 converts an amount of incident light formedinto an image on the imaging surface by the optical unit 101 into anelectric signal on a pixel-by-pixel basis and outputs the electricsignal as a pixel signal.

The DSP circuit 103 performs signal processing on the pixel signaloutput from the imaging device 102. The frame memory 104 is a memory forstoring one screen of a moving image or a still image captured by theimaging device 102.

The display unit 105 includes, for example, a panel type display devicesuch as a liquid crystal panel or an organic EL panel, and displays amoving image or a still image captured by the imaging device 102. Therecording unit 106 records the moving image or still image captured bythe imaging device 102 on a recording medium such as a hard disk or asemiconductor memory.

The operation unit 107 issues operation commands for various functionsof the camera 100 in response to an operation performed by a user. Thepower supply unit 108 appropriately supplies various power supplies,which are operation power supplies for the DSP circuit 103, the framememory 104, the display unit 105, the recording unit 106, and theoperation unit 107, to these power supply targets.

It can be expected to acquire a satisfactory image by using thesolid-state imaging device according to any of the first to seventhembodiments as the imaging device 102.

The solid-state imaging device can be applied to various other products.For example, the solid-state imaging device may be mounted on any typeof mobile bodies such as vehicles, electric vehicles, hybrid electricvehicles, motorcycles, bicycles, personal mobility, airplanes, drones,ships, and robots.

FIG. 17 is a block diagram illustrating a configuration example of amobile body control system. The mobile body control system illustratedin FIG. 17 is a vehicle control system 200.

The vehicle control system 200 includes a plurality of electroniccontrol units connected to each other via a communication network 201.In the example illustrated in FIG. 17 , the vehicle control system 200includes a driving system control unit 210, a body system control unit220, an outside-vehicle information detecting unit 230, an in-vehicleinformation detecting unit 240, and an integrated control unit 250.Moreover, FIG. 17 illustrates a microcomputer 251, a sound/image outputunit 252, and a vehicle-mounted network interface (I/F) 253 ascomponents of the integrated control unit 250.

The driving system control unit 210 controls the operation of devicesrelated to a driving system of a vehicle in accordance with varioustypes of programs. For example, the driving system control unit 210functions as a control device for a driving force generating device forgenerating the driving force of the vehicle, such as an internalcombustion engine, a driving motor, or the like, a driving forcetransmitting mechanism for transmitting the driving force to wheels, asteering mechanism for adjusting the steering angle of the vehicle, abraking device for generating the braking force of the vehicle, and thelike.

The body system control unit 220 controls the operation of various typesof devices provided to a vehicle body in accordance with various typesof programs. For example, the body system control unit 220 functions asa control device for a smart key system, a keyless entry system, a powerwindow device, or various types of lamps (for example, a headlamp, abackup lamp, a brake lamp, a turn signal, a fog lamp, or the like). Inthis case, radio waves transmitted from a mobile device as analternative to a key or signals of various types of switches can beinput to the body system control unit 220. The body system control unit220 receives inputs of such radio waves or signals, and controls a doorlock device, the power window device, the lamps, or the like of thevehicle.

The outside-vehicle information detecting unit 230 detects informationabout the outside of the vehicle including the vehicle control system200. For example, the outside-vehicle information detecting unit 230 isconnected with an imaging unit 231. The outside-vehicle informationdetecting unit 230 makes the imaging unit 231 capture an image of theoutside of the vehicle, and receives the captured image from the imagingunit 231. On the basis of the received image, the outside-vehicleinformation detecting unit 230 may perform processing of detecting anobject such as a human, a vehicle, an obstacle, a sign, a character on aroad surface, or the like, or processing of detecting a distancethereto.

The imaging unit 231 is an optical sensor that receives light and thatoutputs an electric signal corresponding to the amount of receivedlight. The imaging unit 231 can output the electric signal as an image,or can output the electric signal as information about a measureddistance. The light received by the imaging unit 231 may be visiblelight, or may be invisible light such as infrared rays or the like. Theimaging unit 231 includes the solid-state imaging device according toany of the first to seventh embodiments.

The in-vehicle information detecting unit 240 detects information aboutthe inside of the vehicle equipped with the vehicle control system 200.The in-vehicle information detecting unit 240 is, for example, connectedwith a driver state detecting section 241 that detects a state of adriver. The driver state detecting section 241, for example, includes acamera that captures an image of the driver. On the basis of detectioninformation input from the driver state detecting section 241, thein-vehicle information detecting unit 240 may calculate a degree offatigue of the driver or a degree of concentration of the driver, or maydetermine whether or not the driver is dozing. The camera may includethe solid-state imaging device according to any of the first to seventhembodiments, and may be, for example, the camera 100 illustrated in FIG.16 .

The microcomputer 251 can calculate a control target value for thedriving force generating device, the steering mechanism, or the brakingdevice on the basis of the information about the inside or outside ofthe vehicle obtained by the outside-vehicle information detecting unit230 or the in-vehicle information detecting unit 240, and output acontrol command to the driving system control unit 210. For example, themicrocomputer 251 can perform cooperative control intended to implementfunctions of an advanced driver assistance system (ADAS), the functionsincluding collision avoidance or shock mitigation for the vehicle,following driving based on a following distance, vehicle speedmaintaining driving, a warning of collision of the vehicle, a warning ofdeviation of the vehicle from a lane, or the like.

Furthermore, the microcomputer 251 can perform cooperative controlintended for automated driving, which makes the vehicle travelautonomously without depending on the operation of the driver, or thelike, by controlling the driving force generating device, the steeringmechanism, the braking device, or the like on the basis of theinformation about the outside or inside of the vehicle obtained by theoutside-vehicle information detecting unit 230 or the in-vehicleinformation detecting unit 240.

Furthermore, the microcomputer 251 can output a control command to thebody system control unit 220 on the basis of the information about theoutside of the vehicle obtained by the outside-vehicle informationdetecting unit 230. For example, the microcomputer 251 can performcooperative control intended to prevent a glare by controlling theheadlamp so as to change from a high beam to a low beam, for example, inaccordance with the position of a preceding vehicle or an oncomingvehicle detected by the outside-vehicle information detecting unit 230.

The sound/image output unit 252 transmits an output signal of at leastone of a sound or an image to an output device capable of visually orauditorily providing information to an occupant of the vehicle or theoutside of the vehicle. In the example of FIG. 17 , an audio speaker261, a display unit 262, and an instrument panel 263 are illustrated assuch an output device. The display unit 262 may, for example, include anon-board display or a head-up display.

FIG. 18 is a plan view depicting a specific example of a settingposition of the imaging unit 231 in FIG. 17 .

A vehicle 300 illustrated in FIG. 18 includes imaging units 301, 302,303, 304, and 305 as the imaging unit 231. The imaging units 301, 302,303, 304, and 305 are, for example, provided at positions on a frontnose, side mirrors, a rear bumper, and a back door of the vehicle 300,and on an upper portion of a windshield within the interior of thevehicle.

The imaging unit 301 provided on the front nose mainly acquires an imageof the front of the vehicle 300. The imaging unit 302 provided on theleft side mirror and the imaging unit 303 provided on the right sidemirror mainly acquire images of the sides of the vehicle 300. Theimaging unit 304 provided to the rear bumper or the back door mainlyacquires an image of the rear of the vehicle 300. The imaging unit 305provided to the upper portion of the windshield within the interior ofthe vehicle mainly acquires an image of the front of the vehicle 300.The imaging unit 305 is used to detect, for example, a precedingvehicle, a pedestrian, an obstacle, a signal, a traffic sign, a lane,and the like.

FIG. 18 illustrates an example of imaging ranges of the imaging units301, 302, 303, and 304 (hereinafter referred to as “imaging units 301 to304”). An imaging range 311 represents the imaging range of the imagingunit 301 provided to the front nose. An imaging range 312 represents theimaging range of the imaging unit 302 provided to the left side mirror.An imaging range 313 represents the imaging range of the imaging unit303 provided to the right side mirror. An imaging range 314 representsthe imaging range of the imaging unit 304 provided to the rear bumper orthe back door. For example, a bird's-eye image of the vehicle 300 asviewed from above is obtained by superimposing image data captured bythe imaging units 301 to 304, for example. Hereinafter, the imagingranges 311, 312, 313, and 314 are referred to as the “imaging ranges 311to 314”.

At least one of the imaging units 301 to 304 may have a function ofacquiring distance information. For example, at least one of the imagingunits 301 to 304 may be a stereo camera including a plurality of imagingdevices or an imaging device including pixels for phase differencedetection.

For example, the microcomputer 251 (FIG. 17 ) can determine a distanceto each three-dimensional object within the imaging ranges 311 to 314and a temporal change in the distance (relative speed with respect tothe vehicle 300) on the basis of the distance information obtained fromthe imaging units 301 to 304. On the basis of the calculation results,the microcomputer 251 can extract, as a preceding vehicle, a nearestthree-dimensional object that is present on a traveling path of thevehicle 300 and travels in substantially the same direction as thevehicle 300 at a predetermined speed (for example, equal to or more than0 km/h). Moreover, the microcomputer 251 can set a following distance tobe maintained in front of a preceding vehicle in advance, and performautomatic brake control (including following stop control), automaticacceleration control (including following start control), or the like.According to this example, it is thus possible to perform cooperativecontrol intended for automated driving that makes the vehicle travelautonomously without depending on the operation of the driver or thelike.

For example, the microcomputer 251 can classify three-dimensional objectdata on three-dimensional objects into three-dimensional object data ofa two-wheeled vehicle, a standard-sized vehicle, a large-sized vehicle,a pedestrian, a utility pole, and other three-dimensional objects on thebasis of the distance information obtained from the imaging units 301 to304, extract the classified three-dimensional object data, and use theextracted three-dimensional object data for automatic avoidance of anobstacle. For example, the microcomputer 251 identifies obstacles aroundthe vehicle 300 as obstacles that the driver of the vehicle 300 canrecognize visually and obstacles that are difficult for the driver ofthe vehicle 300 to recognize visually. Then, the microcomputer 251determines a collision risk indicating a risk of collision with eachobstacle. In a situation in which the collision risk is equal to orhigher than a set value and there is thus a possibility of collision,the microcomputer 251 outputs a warning to the driver via the audiospeaker 261 or the display unit 262, and performs forced deceleration oravoidance steering via the driving system control unit 210. Themicrocomputer 251 can thereby assist in driving to avoid collision.

At least one of the imaging units 301 to 304 may be an infrared camerathat detects infrared rays. The microcomputer 251 can, for example,recognize a pedestrian by determining whether or not there is apedestrian in captured images captured by the imaging units 301 to 304.Such recognition of a pedestrian is, for example, performed by aprocedure of extracting characteristic points in the captured imagescaptured by the imaging units 301 to 304 as infrared cameras and aprocedure of determining whether or not an object is a pedestrian byperforming pattern matching processing on a series of characteristicpoints representing the contour of the object. When the microcomputer251 determines that there is a pedestrian in the captured imagescaptured by the imaging units 301 to 304, and thus recognizes thepedestrian, the sound/image output unit 252 controls the display unit262 so that a square contour line for emphasis is displayed so as to besuperimposed on the recognized pedestrian. Furthermore, the sound/imageoutput unit 252 may also control the display unit 262 so that an icon orthe like representing the pedestrian is displayed at a desired position.

FIG. 19 is a view illustrating an example of a schematic configurationof an endoscopic surgical system to which the technology of the presentdisclosure (present technology) can be applied.

FIG. 19 illustrates a state in which an operator (doctor) 531 performssurgery on a patient 532 on a patient bed 533 by using an endoscopicsurgical system 400. As illustrated, the endoscopic surgical system 400includes an endoscope 500, other surgical tools 510 such as apneumoperitoneum tube 511 and an energy treatment tool 512, a supportingarm device 520 for supporting the endoscope 500, and a cart 600 on whichvarious devices for endoscopic surgical are mounted.

The endoscope 500 includes a lens barrel 501 having a region of apredetermined length from a distal end thereof to be inserted into abody cavity of the patient 532, and a camera head 502 connected to aproximal end of the lens barrel 501. Although the illustrated exampleillustrates that the endoscope 500 is a so-called rigid endoscope havinga rigid lens barrel 501, the endoscope 500 may be a so-called flexibleendoscope having a flexible lens barrel.

An opening in which an objective lens is fitted is provided at thedistal end of the lens barrel 501. A light source device 603 isconnected to the endoscope 500, and light generated by the light sourcedevice 603 is guided to the distal end of the lens barrel by a lightguide extending in the lens barrel 501 and is emitted to a target to beobserved in the body cavity of the patient 532 through the objectivelens. Note that the endoscope 500 may be a forward-viewing endoscope, anoblique-viewing endoscope, or a side-viewing endoscope.

An optical system and an imaging element are provided in the camera head502, and light reflected by the target to be observed (observationlight) is collected on the imaging element by the optical system. Theimaging element photoelectrically converts the observation light andgenerates an electric signal corresponding to the observation light,that is, an image signal corresponding to an observation image. Theimage signal is transmitted to a camera control unit (CCU) 601 as RAWdata.

The CCU 601 includes a central processing unit (CPU), a graphicsprocessing unit (GPU), and the like, and centrally controls theoperations of the endoscope 500 and a display device 602. Moreover, theCCU 601 receives the image signal from the camera head 502 and appliesvarious types of image processing for displaying an image based on theimage signal, for example, a development process (demosaicing process)and the like on the image signal.

The display device 602 displays the image based on the image signalwhich has been subjected to the image processing by the CCU 601 underthe control of the CCU 601.

The light source device 603 includes a light source such as a lightemitting diode (LED), for example, and supplies irradiation light forimaging a surgical site or the like to the endoscope 500.

An input device 604 is an input interface for the endoscopic surgicalsystem 11000. A user may input various types of information andinstructions to the endoscopic surgical system 400 via the input device604. For example, the user inputs an instruction and the like to changean imaging condition (type of irradiation light, magnification, focallength and the like) by the endoscope 500.

A treatment tool control device 605 controls driving of the energytreatment tool 512 for tissue cauterization, incision, blood vesselsealing, and the like. A pneumoperitoneum device 606 sends gas into thebody cavity of the patient 532 via the pneumoperitoneum tube 511 inorder to inflate the body cavity for a purpose of securing a field ofview by the endoscope 500 and securing work space for the operator. Arecorder 607 is a device capable of recording various types ofinformation regarding surgery. A printer 608 is a device capable ofprinting various types of information regarding surgery in variousformats such as a text, an image, or a graph.

Note that, the light source device 603 which supplies the irradiationlight for imaging the surgical site to the endoscope 500 may include,for example, an LED, a laser light source, or a white light sourceobtained by combining these. In a case where the white light sourceincludes a combination of RGB laser light sources, an output intensityand an output timing of each color (each wavelength) can be controlledwith high accuracy, whereby the light source device 603 can adjust whitebalance of a captured image. Furthermore, in this case, imagesrespectively corresponding to the R, G, and B can also be captured intime division by irradiating the target to be observed with laser lightfrom each of the RGB laser light sources in time division, andcontrolling the driving of the imaging element of the camera head 502 insynchronization with the irradiation timing. According to this method, acolor image can be obtained even if color filters are not provided forthe imaging element.

Furthermore, the driving of the light source device 603 may becontrolled such that the intensity of light to be output is changedevery predetermined time. The driving of the imaging element of thecamera head 502 is controlled in synchronization with a timing ofchanging the light intensity to obtain the images in time division, andthe obtained images are synthesized, whereby an image with a highdynamic range that does not have so-called blocked up shadows andblown-out highlights can be generated.

Furthermore, the light source device 603 may be able to supply light ina predetermined wavelength band adapted to special light observation. Inthe special light observation, for example, light in a narrower bandthan irradiation light (in other words, white light) at the time ofnormal observation is emitted using wavelength dependency of a bodytissue to absorb light, whereby so-called narrow band imaging isperformed in which an image of a predetermined tissue, such as a bloodvessel in a mucosal surface layer, is captured with high contrast.Alternatively, in the special light observation, fluorescenceobservation for obtaining an image by fluorescence generated byirradiation of excitation light may be performed. In the fluorescenceobservation, it is possible to irradiate a body tissue with excitationlight to observe fluorescence from the body tissue (autofluorescenceobservation) or to locally inject a reagent such as indocyanine green(ICG) to a body tissue and irradiate the body tissue with excitationlight corresponding to a fluorescent wavelength of the reagent, therebyobtaining a fluorescent image, for example. The light source device 603can be configured to be able to supply narrow band light and/orexcitation light adapted to such special light observation.

FIG. 20 is a block diagram illustrating an example of functionalconfigurations of the camera head 502 and the CCU 601 illustrated inFIG. 19 .

The camera head 502 includes a lens unit 701, an imaging unit 702, adrive unit 703, a communication unit 704, and a camera head controller705. The CCU 601 includes a communication unit 711, an image processingunit 712, and a controller 713. The camera head 502 and the CCU 601 areconnected to each other so as to be able to communicate by atransmission cable 700.

The lens unit 701 is an optical system provided at a connecting portionwith the lens barrel 501. The observation light captured from the distalend of the lens barrel 501 is guided to the camera head 502 and entersthe lens unit 701. The lens unit 701 is configured by combining aplurality of lenses including a zoom lens and a focus lens.

The imaging unit 702 includes an imaging element. The number of imagingelement constituting the imaging unit 702 may be one (so-called singleplate type) or two or more (so-called multiple plate type). In a casewhere the imaging unit 702 is of the multiple plate type, image signalscorresponding to R, G, and B may be generated by the respective imagingelements, and a color image may be obtained by combining the generatedimage signals, for example. Alternatively, the imaging unit 702 mayinclude a pair of imaging elements for obtaining right-eye and left-eyeimage signals corresponding to three-dimensional (3D) display. By the 3Ddisplay, the operator 531 can grasp a depth of a living body tissue in asurgical site more accurately. Note that, in a case where the imagingunit 702 is of the multiple plate type, a plurality of systems of lensunits 701 may be provided so as to correspond to the respective imagingelements. The imaging unit 702 is, for example, the solid-state imagingdevice according to any of the first to seventh embodiments.

Furthermore, the imaging unit 702 is not necessarily provided in thecamera head 502. For example, the imaging unit 702 may be providedinside the lens barrel 501 immediately behind the objective lens.

The drive unit 703 includes an actuator and moves the zoom lens and thefocusing lens of the lens unit 701 by a predetermined distance along anoptical axis under the control of the camera head controller 705.Therefore, the magnification and focal point of the image captured bythe imaging unit 702 may be appropriately adjusted.

The communication unit 704 includes a communication device fortransmitting and receiving various types of information to and from theCCU 601. The communication unit 704 transmits the image signal obtainedfrom the imaging unit 702 as the RAW data to the CCU 601 via thetransmission cable 700.

Furthermore, the communication unit 704 receives a control signal forcontrolling driving of the camera head 502 from the CCU 601 and suppliesthe control signal to the camera head controller 705. The control signalincludes, for example, information regarding an imaging condition suchas information specifying a frame rate of a captured image, informationspecifying an exposure value at the time of imaging, and/or informationspecifying the magnification and focal point of the captured image.

Note that the imaging conditions such as the frame rate, exposure value,magnification, and focus described above may be appropriately specifiedby the user, or may be automatically set by the controller 713 of theCCU 601 on the basis of the acquired image signal. In the latter case,the endoscope 500 is equipped with a so-called auto exposure (AE)function, an auto focus (AF) function, and an auto white balance (AWB)function.

The camera head controller 705 controls the driving of the camera head502 on the basis of the control signal from the CCU 601 received via thecommunication unit 704.

The communication unit 711 includes a communication device fortransmitting and receiving various types of information to and from thecamera head 502. The communication unit 711 receives the image signaltransmitted from the camera head 502 via the transmission cable 700.

Furthermore, the communication unit 711 transmits the control signal forcontrolling the driving of the camera head 502 to the camera head 502.The image signal and the control signal can be transmitted by electricalcommunication, optical communication or the like.

The image processing unit 712 performs various types of image processingon the image signal which is the RAW data transmitted from the camerahead 502.

The controller 713 performs various types of control regarding imagingof the surgical site and the like by the endoscope 500 and display ofthe captured image obtained by the imaging of the surgical site and thelike. For example, the controller 713 generates the control signal forcontrolling the driving of the camera head 502.

Furthermore, the controller 713 allows the display device 602 to displaythe captured image including the surgical site and the like on the basisof the image signal subjected to the image processing by the imageprocessing unit 712. At that time, the controller 713 may recognizevarious objects in the captured image using various image recognitiontechnologies. For example, the controller 713 may detect edge shapes,colors, and the like of the objects included in the captured image,thereby recognizing the surgical tool such as forceps, a specific livingbody site, bleeding, mist when the energy treatment tool 512 is used,and the like. When causing the display device 602 to display thecaptured image, the controller 713 may overlay various types of surgeryassistance information on the image of the surgical site using therecognition result. The surgery support information is displayed to beoverlaid and presented to the operator 531, so that it is possible toreduce the burden on the operator 531 and enable the operator 531 toreliably proceed with surgery.

The transmission cable 700 connecting the camera head 502 and the CCU601 is an electric signal cable compatible with communication ofelectric signals, an optical fiber compatible with opticalcommunication, or a composite cable thereof.

Here, the communication is performed by wire using the transmissioncable 700 in the illustrated example, but the communication between thecamera head 502 and the CCU 601 may be performed wirelessly.

Although the embodiments of the present disclosure have been describedabove, these embodiments may be implemented with various modificationswithin a scope not departing from the gist of the present disclosure.For example, two or more embodiments may be implemented in combination.

Note that the present disclosure can also have the followingconfigurations.

(1)

A solid-state imaging device including:

-   -   first and second photoelectric conversion units that are        provided in a first semiconductor substrate and are adjacent to        each other;    -   a first pixel separation groove provided between the first        photoelectric conversion unit and the second photoelectric        conversion unit not to penetrate through the first semiconductor        substrate; and    -   a second pixel separation groove provided to penetrate through        the first semiconductor substrate.

(2)

The solid-state imaging device according to (1), in which the firstpixel separation groove is provided from a side of a light incidentsurface of the first semiconductor substrate toward a surface of thefirst semiconductor substrate on a side opposite to the light reflectingsurface.

(3)

The solid-state imaging device according to (1), in which the secondpixel separation groove is provided to surround at least the first andsecond photoelectric conversion units in a plan view.

(4)

The solid-state imaging device according to (1), in which the secondpixel separation groove forms a pixel separation groove that surroundsthe first and second photoelectric conversion units for each of thephotoelectric conversion units together with the first pixel separationgroove.

(5)

The solid-state imaging device according to (1), in which the secondpixel separation groove is further provided between the firstphotoelectric conversion unit and the second photoelectric conversionunit together with the first pixel separation groove.

(6)

The solid-state imaging device according to (1), in which

-   -   the second pixel separation groove surrounds N photoelectric        conversion units (N is an integer of two or more) including the        first and second photoelectric conversion units, and    -   the N photoelectric conversion units correspond to one on-chip        lens provided on the first semiconductor substrate.

(7)

The solid-state imaging device according to (6), in which the Nphotoelectric conversion units are provided in N pixels which are pixelsof an identical color.

(8)

The solid-state imaging device according to (1), in which

-   -   the second pixel separation groove surrounds N photoelectric        conversion units (N is an integer of two or more) including the        first and second photoelectric conversion units, and    -   the N photoelectric conversion units correspond to two lenses        provided on the first semiconductor substrate.

(9)

The solid-state imaging device according to (1), in which

-   -   the second pixel separation groove surrounds N photoelectric        conversion units (N is an integer of two or more) including the        first and second photoelectric conversion units, and    -   the N photoelectric conversion units correspond to N on-chip        lenses provided on the first semiconductor substrate.

(10)

The solid-state imaging device according to (9), in which the N is asquare of K (K is an integer of three or more).

(11)

The solid-state imaging device according to (1), further including afloating diffusion unit provided at a position at least partiallyoverlapping the first pixel separation groove in a plan view in thefirst semiconductor substrate.

(12)

The solid-state imaging device according to (11), in which

-   -   the first pixel separation groove includes a first portion        extending in a first direction and a second portion extending in        a second direction, and    -   the floating diffusion unit is provided at a position at least        partially overlapping an intersection portion between the first        portion and the second portion in a plan view in the first        semiconductor substrate.

(13)

The solid-state imaging device according to (1), in which

-   -   the first pixel separation groove includes a first portion        extending in a first direction and a second portion extending in        a second direction, and    -   the first direction and the second direction are non-parallel        and non-perpendicular to an end surface of a chip including the        solid-state imaging device.

(14)

The solid-state imaging device according to (1), further including firstand second transfer transistors that are provided under the first andsecond photoelectric conversion units and have gate electrodes,respectively, being at least partially provided in a first interlayerinsulating film.

(15)

The solid-state imaging device according to (14), in which

-   -   the second pixel separation groove surrounds N photoelectric        conversion units (N is an integer of two or more) including the        first and second photoelectric conversion units,    -   the solid-state imaging device further includes a reset,        selection, or amplification transistor provided under any        photoelectric conversion unit of the N photoelectric conversion        units, and    -   the first transfer transistor, the second transfer transistor,        and the reset, selection, or amplification transistor being        provided on the surface of the first semiconductor substrate on        the side opposite to the light incident surface.

(16)

The solid-state imaging device according to (15), further including asecond semiconductor substrate that is provided to face a firstinterlayer insulating film provided on a surface of the firstsemiconductor substrate on a side opposite to a light incident surface,

-   -   in which the second semiconductor substrate includes at least a        part of a pixel transistor other than the transfer transistors.

(17)

A solid-state imaging device including:

-   -   first and second photoelectric conversion units that are        provided in the first semiconductor substrate and are adjacent        to each other;    -   a floating diffusion unit provided in the first semiconductor        substrate; and    -   first and second transfer transistors respectively provided        under the first and second photoelectric conversion units,    -   in which the first and second transfer transistors operate to        provide    -   a first mode in which a path of a charge from the first        photoelectric conversion unit to the floating diffusion unit is        closed and a path of a charge from the first photoelectric        conversion unit to the second photoelectric conversion unit is        closed,    -   a second mode in which the path of the charge from the first        photoelectric conversion unit to the floating diffusion unit is        closed, and the path of the charge from the first photoelectric        conversion unit to the second photoelectric conversion unit is        opened, and    -   a third mode in which the path of the charge from the first        photoelectric conversion unit to the floating diffusion unit is        opened.

(18)

The solid-state imaging device according to (17), further including afirst pixel separation groove provided between the first photoelectricconversion unit and the second photoelectric conversion unit not topenetrate through the first semiconductor substrate,

-   -   in which the floating diffusion unit is provided under the first        pixel separation groove in the first semiconductor substrate.

(19)

The solid-state imaging device according to (18), further including asecond pixel separation groove provided to penetrate through the firstsemiconductor substrate,

-   -   in which the second pixel separation groove is provided to        surround at least the first and second photoelectric conversion        units in a plan view.

(20)

The solid-state imaging device according to (19), further including asecond semiconductor substrate that is provided to face a firstinterlayer insulating film provided on a surface of the firstsemiconductor substrate on a side opposite to a light incident surface,

-   -   in which the second semiconductor substrate includes at least a        part of a pixel transistor other than the transfer transistors.

REFERENCE SIGNS LIST

-   -   1 Pixel    -   2 Pixel array region    -   3 Control circuit    -   4 Vertical drive circuit    -   5 Column signal processing circuit    -   6 Horizontal drive circuit    -   7 Output circuit    -   8 Vertical signal line    -   9 Horizontal signal line    -   11 Upper substrate    -   12 Intermediate substrate    -   13 Lower substrate    -   14 Light shielding film    -   15 Planarization film    -   16 Color filter    -   17 On-chip lens    -   21 First semiconductor substrate    -   21 a n type semiconductor region    -   21 b p+ type semiconductor region    -   21 c p type semiconductor region    -   21 d n type semiconductor region    -   21 e n type semiconductor region    -   22 First interlayer insulating film    -   23 Gate insulating film    -   24 Gate electrode    -   25 Insulating film    -   26 Insulating film    -   31 Second semiconductor substrate    -   31 a Impurity semiconductor region    -   32 Second interlayer insulating film    -   32 a Insulating film    -   32 b Insulating film    -   33 Gate insulating film    -   34 Gate electrode    -   35 Plug    -   36 First wiring layer    -   37 Second wiring layer    -   38 Third wiring layer    -   39 Fourth wiring layer    -   41 Third semiconductor substrate    -   41 a Impurity semiconductor region    -   42 Third interlayer insulating film    -   42 a Insulating film    -   42 b Insulating film    -   43 Gate insulating film    -   44 Gate electrode    -   45 Plug    -   46 Fifth wiring layer    -   47 Sixth wiring layer    -   48 Seventh wiring layer

1. A solid-state imaging device comprising: first and secondphotoelectric conversion units that are provided in a firstsemiconductor substrate and are adjacent to each other; a first pixelseparation groove provided between the first photoelectric conversionunit and the second photoelectric conversion unit not to penetratethrough the first semiconductor substrate; and a second pixel separationgroove provided to penetrate through the first semiconductor substrate.2. The solid-state imaging device according to claim 1, wherein thefirst pixel separation groove is provided from a side of a lightincident surface of the first semiconductor substrate toward a surfaceof the first semiconductor substrate on a side opposite to the lightreflecting surface.
 3. The solid-state imaging device according to claim1, wherein the second pixel separation groove is provided to surround atleast the first and second photoelectric conversion units in a planview.
 4. The solid-state imaging device according to claim 1, whereinthe second pixel separation groove forms a pixel separation groove thatsurrounds the first and second photoelectric conversion units for eachof the photoelectric conversion units together with the first pixelseparation groove.
 5. The solid-state imaging device according to claim1, wherein the second pixel separation groove is further providedbetween the first photoelectric conversion unit and the secondphotoelectric conversion unit together with the first pixel separationgroove.
 6. The solid-state imaging device according to claim 1, whereinthe second pixel separation groove surrounds N photoelectric conversionunits (N is an integer of two or more) including the first and secondphotoelectric conversion units, and the N photoelectric conversion unitscorrespond to one on-chip lens provided on the first semiconductorsubstrate.
 7. The solid-state imaging device according to claim 6,wherein the N photoelectric conversion units are provided in N pixelswhich are pixels of an identical color.
 8. The solid-state imagingdevice according to claim 1, wherein the second pixel separation groovesurrounds N photoelectric conversion units (N is an integer of two ormore) including the first and second photoelectric conversion units, andthe N photoelectric conversion units correspond to two lenses providedon the first semiconductor substrate.
 9. The solid-state imaging deviceaccording to claim 1, wherein the second pixel separation groovesurrounds N photoelectric conversion units (N is an integer of two ormore) including the first and second photoelectric conversion units, andthe N photoelectric conversion units correspond to N on-chip lensesprovided on the first semiconductor substrate.
 10. The solid-stateimaging device according to claim 9, wherein the N is a square of K (Kis an integer of three or more).
 11. The solid-state imaging deviceaccording to claim 1, further comprising a floating diffusion unitprovided at a position at least partially overlapping the first pixelseparation groove in a plan view in the first semiconductor substrate.12. The solid-state imaging device according to claim 11, wherein thefirst pixel separation groove includes a first portion extending in afirst direction and a second portion extending in a second direction,and the floating diffusion unit is provided at a position at leastpartially overlapping an intersection portion between the first portionand the second portion in a plan view in the first semiconductorsubstrate.
 13. The solid-state imaging device according to claim 1,wherein the first pixel separation groove includes a first portionextending in a first direction and a second portion extending in asecond direction, and the first direction and the second direction arenon-parallel and non-perpendicular to an end surface of a chip includingthe solid-state imaging device.
 14. The solid-state imaging deviceaccording to claim 1, further comprising first and second transfertransistors that are provided under the first and second photoelectricconversion units and have gate electrodes, respectively, being at leastpartially provided in a first interlayer insulating film.
 15. Thesolid-state imaging device according to claim 14, wherein the secondpixel separation groove surrounds N photoelectric conversion units (N isan integer of two or more) including the first and second photoelectricconversion units, the solid-state imaging device further comprises areset, selection, or amplification transistor provided under anyphotoelectric conversion unit of the N photoelectric conversion units,and the first transfer transistor, the second transfer transistor, andthe reset, selection, or amplification transistor being provided on thesurface of the first semiconductor substrate on the side opposite to thelight incident surface.
 16. The solid-state imaging device according toclaim 15, further comprising a second semiconductor substrate that isprovided to face the first interlayer insulating film provided on thesurface of the first semiconductor substrate on the side opposite to thelight incident surface, wherein the second semiconductor substrateincludes at least a part of a pixel transistor other than the transfertransistors.
 17. A solid-state imaging device comprising: first andsecond photoelectric conversion units that are provided in the firstsemiconductor substrate and are adjacent to each other; a floatingdiffusion unit provided in the first semiconductor substrate; and firstand second transfer transistors respectively provided under the firstand second photoelectric conversion units, wherein the first and secondtransfer transistors operate to provide a first mode in which a path ofa charge from the first photoelectric conversion unit to the floatingdiffusion unit is closed and a path of a charge from the firstphotoelectric conversion unit to the second photoelectric conversionunit is closed, a second mode in which the path of the charge from thefirst photoelectric conversion unit to the floating diffusion unit isclosed, and the path of the charge from the first photoelectricconversion unit to the second photoelectric conversion unit is opened,and a third mode in which the path of the charge from the firstphotoelectric conversion unit to the floating diffusion unit is opened.18. The solid-state imaging device according to claim 17, furthercomprising a first pixel separation groove provided between the firstphotoelectric conversion unit and the second photoelectric conversionunit not to penetrate through the first semiconductor substrate, whereinthe floating diffusion unit is provided under the first pixel separationgroove in the first semiconductor substrate.
 19. The solid-state imagingdevice according to claim 18, further comprising a second pixelseparation groove provided to penetrate through the first semiconductorsubstrate, wherein the second pixel separation groove is provided tosurround at least the first and second photoelectric conversion units ina plan view.
 20. The solid-state imaging device according to claim 19,further comprising a second semiconductor substrate that is provided toface a first interlayer insulating film provided on a surface of thefirst semiconductor substrate on a side opposite to a light incidentsurface, wherein the second semiconductor substrate includes at least apart of a pixel transistor other than the transfer transistors.